Not all organisms are rendered sluggish by the heat. The algae in Trafalgar Square's fountains are multiplying like tiny autotrophic rabbits. Two of the historic pools have been closed for cleaning following a break-down of the filters. The choked-out water features only reopened a few weeks ago following installation of a new lighting system (which, ironically, was predicted to make the fountains 'go green'). It's a simple fix, though, and the fountains should be back in action in time for this weekend's Pride parade.